Angular stomatitis and riboflavin status among adolescent Bhutanese refugees living in southeastern Nepal

Between 1990 and 1993, fear of ethnic persecution led 83,000 ethnic Nepalese to flee from Bhutan to refugee camps in Nepal, where they remained at the time of this study. Reported cases of angular stomatitis (AS), ie, thinning or fissuring at the mouth angles, increased 6-fold from December 1998 to March 1999, from 5.5 to 35.6 cases per 1000 per month. This increase came after the removal of a fortified cereal from rations.

The main objectives were to assess the prevalence of AS and of low concentrations of riboflavin, folate, vitamin B-12, and iron by using biochemical measures; to determine whether riboflavin status was associated with AS; and to assess the potential of AS as a screening measure for low riboflavin concentrations.

In October 1999, we performed a survey among a random sample of 463 adolescent refugees in which we conducted interviews and physical examinations and obtained blood specimens for riboflavin assessment. Riboflavin status was assessed with the erythrocyte glutathione reductase (EC 1.6.4.2) activity coefficient. After we excluded those adolescents who had taken vitamins during the past month, 369 were eligible for analyses.

AS was common (26.8%; 95% CI: 22.3, 31.3), the prevalence of low riboflavin concentrations was high (85.8%; 80.7, 90.9), and riboflavin status was associated with AS. Adolescents with AS had significantly lower riboflavin concentrations than did adolescents without AS (P = 0.02). The adjusted odds ratio for AS and low riboflavin concentrations was 5.1 (1.55, 16.5).

Globally, riboflavin deficiency is rare. Its emergence in food-dependent populations can be a harbinger of other B-vitamin deficiencies.